1. Field of the Invention
The present invention relates to an image capturing device, in particular to the image capturing device capable of automatically switching the clock of a memory and a control method thereof to save power consumption during the operation of the image capturing device.
2. Description of the Related Art
In recent years, electronic devices with an image capturing function such as mobile phones, digital still cameras and digital video cameras become increasingly more popular. In the development of these portable electronic devices, how to lower the power consumption is always an important issue. If the working clock can be adjusted dynamically without affecting the operation performance and certain functions can be executed at a slower clock, the power consumption can be reduced effectively.
For example, when the digital still camera is operated in a live view mode, the resolution of captured images is lower so that DRAM serving as an image buffer can be operated at a lower working clock for storing data. When the digital still camera is operated in photographing mode to take pictures, compared to the live view mode, the captured images have a higher resolution and thus the DRAM must be operated at a higher clock for storing data and providing a higher resolution for the captured images.
However, the image capturing device available in the market is operated at a working clock of the same frequency regardless of being executed at both the live view mode and photographing mode, and thus cause electric power wasting. Therefore, it is a main subject for the present invention to adjust the working clock without affecting the quality of capturing images and displaying the images immediately by the image capturing device.